1. Field of the Invention
The present invention relates to a feed system and, more particularly, to a feed system capable of carrying a moving body back and forth by using an actuator.
2. Description of the Prior Art
A feed system making use of the electroeletricity of the actuator is exemplified in the prior art by a piezoelectric linear actuator of inch worm type.
FIG. 8 is a section showing a piezoelectric linear actuator of this conventional type. In FIG. 8, reference numerals 1 and 2 designate a stationary support member and a movable support member, respectively, which are juxtaposed at a predetermined Spacing to each other. In these support members 1 and 2, there are fitted bearing cylinders 5 and 6 which are coaxially fastened by fastening screws 3 and 4, respectively. Between the bearing cylinders 5 and 6, there is reciprocally supported a moving body 7 which is to be clamped and unclamped by clamping actuators 8 and 9 fitted in the bearing cylinders 5 and 6, respectively. Moreover, the stationary support member 1 and the movable support member 2 are connected by a moving actuator 10.
In the piezoelectric linear actuator thus constructed, a voltage having a square waveform is intermittently applied at a phase timing, as shown in FIG. 9, to the clamping actuators 8 and 9 and the moving actuator 10. Then, the actuators 8 and 9 are extended and contracted to clamp and unclamp the moving body 7. Simultaneously with this, the actuator 10 is also extended and contracted to carry the moving body 7 intermittently forward or backward.
Since, however, what is effected by such conventional feed system is the intermittent feed, the system can be used merely as positioning means. Thus, there arises a problem that the conventional system cannot be used as a smooth feeder such as a tool feeder in a machine tool.